Linux Server Configuration

14.1 Installation

To install postfix run the following command:
$ sudo apt-get install postfix
Simply press return when the installation process asks questions, the configuration will be done in greater detail in the next stage.

14.2 Basic Configuration

To configure postfix, run the following command:
$ sudo dpkg-reconfigure postfix
The user interface will be displayed. On each screen, select the following values:

• 
  Internet Site
  
• 
  mail.example.com
  
• 
  steve
  
• 
  mail.example.com, localhost.localdomain, localhost
  
• 
  No
  
• 
  127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 192.168.0/24
  
• 
  0
  
• 
  +
  
• 
  All
  

Replace mail.example.com with your mail server hostname, 192.168.0/24 with the actual network and class range of your mail server, and steve with the appropriate username.

SMTP Authentication
SMTP-AUTH allows a client to identify itself through an authentication mechanism (SASL). Transport Layer Security (TLS) should be used to encrypt the authentication process. Once authenticated the SMTP server will allow the client to relay mail.
Configuring Postfix for SMTP-AUTH is very simple using the dovecot-postfix package. This package will install Dovecot and configure Postfix to use it for both SASL authentication and as a Mail Delivery Agent (MDA). The package also configures Dovecot for IMAP, IMAPS, POP3, and POP3S.
To install the package, from a terminal prompt enter:
$ sudo apt-get install dovecot-postfix
You should now have a working mail server, but there are a few options that you may wish to further customize. For example, the package uses the certificate and key from the ssl-cert package, and in a production environment you should use a certificate and key generated for the host.
Once you have a customized certificate and key for the host, change the following options in /etc/postfix/main.cf:
smtpd_tls_cert_file = /etc/ssl/certs/ssl-mail.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-mail.key
Then restart Postfix: